What is responsible for the apparent change in weight that riders experience on roller coasters?

A rectangular wire loop of length $L$ and width $w$ carries a current $I$ and is placed in a uniform magnetic field $B$ such that the plane of the loop is parallel to the field. What is the magnitude of the total force on the loop?

A positive charge $b$ is placed between two other positive charges of equal magnitude, one to its left and one to its right. Four arrows (A, B, C, D) point: A to the right, B to the left, C upward, and D downward. Which of the arrows is in the direction of the net force on charge $b$?

A $1.0\mathrm{kg}$ block hangs at rest from a rope that is attached to a wall. If the block is in equilibrium and the rope is perfectly vertical, what is the tension in the rope?

A block of mass $m$ hangs at rest from a rope attached to the ceiling. What is the tension $T$ in the rope?

At the very top of her swing, does the rope supporting the swing exert a force on the girl, and if so, what is the direction of this force?

Two forces, $F_1$ and $F_2$, act on an object at angles ${\theta }_1$ and ${\theta }_2$ with respect to the x-axis. What is the x component of the resultant force?

Which of the following factors most directly determine how much $F$ an object exerts when it collides with another object?